/**
 * Author(s): xuming.Wong <xuming.Wong@gmail.com>
 */
#include <QtGui/QtGui>
#include "FlowLayout.h"

namespace PQBuilder
{
	 FlowLayout::FlowLayout(QWidget *parent, int margin, int hSpacing, int vSpacing)
		 : QLayout(parent), _hSpace(hSpacing), _vSpace(vSpacing)
	 {
		 setContentsMargins(margin, margin, margin, margin);
	 }

	 FlowLayout::FlowLayout(int margin, int hSpacing, int vSpacing)
		 : _hSpace(hSpacing), _vSpace(vSpacing)
	 {
		 setContentsMargins(margin, margin, margin, margin);
	 }

	 FlowLayout::~FlowLayout()
	 {
		 QLayoutItem *item;
		 while ((item = takeAt(0)))
			 delete item;
	 }

	 void FlowLayout::addItem(QLayoutItem *item)
	 {
		 itemList.append(item);
	 }

	 int FlowLayout::horizontalSpacing() const
	 {
		 if (_hSpace >= 0) {
			 return _hSpace;
		 } else {
			 return smartSpacing(QStyle::PM_LayoutHorizontalSpacing);
		 }
	 }

	 int FlowLayout::verticalSpacing() const
	 {
		 if (_vSpace >= 0) {
			 return _vSpace;
		 } else {
			 return smartSpacing(QStyle::PM_LayoutVerticalSpacing);
		 }
	 }

	 int FlowLayout::count() const
	 {
		 return itemList.size();
	 }

	 QLayoutItem *FlowLayout::itemAt(int index) const
	 {
		 return itemList.value(index);
	 }

	 QLayoutItem *FlowLayout::takeAt(int index)
	 {
		 if (index >= 0 && index < itemList.size())
			 return itemList.takeAt(index);
		 else
			 return 0;
	 }

	 Qt::Orientations FlowLayout::expandingDirections() const
	 {
		 return 0;
	 }

	 bool FlowLayout::hasHeightForWidth() const
	 {
		 return true;
	 }

	 int FlowLayout::heightForWidth(int width) const
	 {
		 int height = doLayout(QRect(0, 0, width, 0), true);
		 return height;
	 }

	 void FlowLayout::setGeometry(const QRect &rect)
	 {
		 QLayout::setGeometry(rect);
		 doLayout(rect, false);
	 }

	 QSize FlowLayout::sizeHint() const
	 {
		 return minimumSize();
	 }

	 QSize FlowLayout::minimumSize() const
	 {
		 QSize size;
		 QLayoutItem *item;
		 foreach (item, itemList)
			 size = size.expandedTo(item->minimumSize());

		 size += QSize(2*margin(), 2*margin());
		 return size;
	 }

	 int FlowLayout::doLayout(const QRect &rect, bool testOnly) const
	 {
		 int left, top, right, bottom;
		 getContentsMargins(&left, &top, &right, &bottom);
		 QRect effectiveRect = rect.adjusted(+left, +top, -right, -bottom);
		 int x = effectiveRect.x();
		 int y = effectiveRect.y();
		 int lineHeight = 0;

		 QLayoutItem *item;
		 foreach (item, itemList) {
			 QWidget *wid = item->widget();
			 int spaceX = horizontalSpacing();
			 if (spaceX == -1)
				 spaceX = wid->style()->layoutSpacing(
					 QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Horizontal);
			 int spaceY = verticalSpacing();
			 if (spaceY == -1)
				 spaceY = wid->style()->layoutSpacing(
					 QSizePolicy::PushButton, QSizePolicy::PushButton, Qt::Vertical);
			 int nextX = x + item->sizeHint().width() + spaceX;
			 if (nextX - spaceX > effectiveRect.right() && lineHeight > 0) {
				 x = effectiveRect.x();
				 y = y + lineHeight + spaceY;
				 nextX = x + item->sizeHint().width() + spaceX;
				 lineHeight = 0;
			 }

			 if (!testOnly)
				 item->setGeometry(QRect(QPoint(x, y), item->sizeHint()));

			 x = nextX;
			 lineHeight = qMax(lineHeight, item->sizeHint().height());
		 }
		 return y + lineHeight - rect.y() + bottom;
	 }
	 int FlowLayout::smartSpacing(QStyle::PixelMetric pm) const
	 {
		 QObject *parent = this->parent();
		 if (!parent) {
			 return -1;
		 } else if (parent->isWidgetType()) {
			 QWidget *pw = static_cast<QWidget *>(parent);
			 return pw->style()->pixelMetric(pm, 0, pw);
		 } else {
			 return static_cast<QLayout *>(parent)->spacing();
		 }
	 }
}
